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41c52c0db9
While debugging latencies in the RT kernel, I found that it would be nice
to be able to filter away functions from the trace than just to filter
on functions.
I added a new interface to the debugfs tracing directory called
set_ftrace_notrace
When dynamic frace is enabled, this lets you filter away functions that will
not be recorded in the trace. It is similar to adding 'notrace' to those
functions but by doing it without recompiling the kernel.
Here's how set_ftrace_filter and set_ftrace_notrace interact. Remember, if
set_ftrace_filter is set, it removes all functions from the trace execpt for
those listed in the set_ftrace_filter. set_ftrace_notrace will prevent those
functions from being traced.
If you were to set one function in both set_ftrace_filter and
set_ftrace_notrace and that function was the same, then you would end up
with an empty trace.
the set of functions to trace is:
set_ftrace_filter == empty then
all functions not in set_ftrace_notrace
else
set of the set_ftrace_filter and not in set of set_ftrace_notrace.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
133 lines
4 KiB
C
133 lines
4 KiB
C
#ifndef _LINUX_FTRACE_H
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#define _LINUX_FTRACE_H
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#ifdef CONFIG_FTRACE
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#include <linux/linkage.h>
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#include <linux/fs.h>
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extern int ftrace_enabled;
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extern int
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ftrace_enable_sysctl(struct ctl_table *table, int write,
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struct file *filp, void __user *buffer, size_t *lenp,
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loff_t *ppos);
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typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
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struct ftrace_ops {
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ftrace_func_t func;
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struct ftrace_ops *next;
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};
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/*
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* The ftrace_ops must be a static and should also
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* be read_mostly. These functions do modify read_mostly variables
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* so use them sparely. Never free an ftrace_op or modify the
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* next pointer after it has been registered. Even after unregistering
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* it, the next pointer may still be used internally.
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*/
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int register_ftrace_function(struct ftrace_ops *ops);
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int unregister_ftrace_function(struct ftrace_ops *ops);
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void clear_ftrace_function(void);
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extern void ftrace_stub(unsigned long a0, unsigned long a1);
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extern void mcount(void);
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#else /* !CONFIG_FTRACE */
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# define register_ftrace_function(ops) do { } while (0)
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# define unregister_ftrace_function(ops) do { } while (0)
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# define clear_ftrace_function(ops) do { } while (0)
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#endif /* CONFIG_FTRACE */
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#ifdef CONFIG_DYNAMIC_FTRACE
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# define FTRACE_HASHBITS 10
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# define FTRACE_HASHSIZE (1<<FTRACE_HASHBITS)
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enum {
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FTRACE_FL_FREE = (1 << 0),
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FTRACE_FL_FAILED = (1 << 1),
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FTRACE_FL_FILTER = (1 << 2),
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FTRACE_FL_ENABLED = (1 << 3),
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FTRACE_FL_NOTRACE = (1 << 4),
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};
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struct dyn_ftrace {
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struct hlist_node node;
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unsigned long ip;
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unsigned long flags;
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};
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int ftrace_force_update(void);
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void ftrace_set_filter(unsigned char *buf, int len, int reset);
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/* defined in arch */
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extern int ftrace_ip_converted(unsigned long ip);
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extern unsigned char *ftrace_nop_replace(void);
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extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
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extern int ftrace_dyn_arch_init(void *data);
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extern int ftrace_mcount_set(unsigned long *data);
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extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
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unsigned char *new_code);
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extern int ftrace_update_ftrace_func(ftrace_func_t func);
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extern void ftrace_caller(void);
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extern void ftrace_call(void);
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extern void mcount_call(void);
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#else
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# define ftrace_force_update() ({ 0; })
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# define ftrace_set_filter(buf, len, reset) do { } while (0)
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#endif
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/* totally disable ftrace - can not re-enable after this */
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void ftrace_kill(void);
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static inline void tracer_disable(void)
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{
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#ifdef CONFIG_FTRACE
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ftrace_enabled = 0;
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#endif
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}
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#ifdef CONFIG_FRAME_POINTER
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/* TODO: need to fix this for ARM */
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
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# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
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# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
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# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
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# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
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# define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
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#else
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 0UL
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# define CALLER_ADDR2 0UL
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# define CALLER_ADDR3 0UL
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# define CALLER_ADDR4 0UL
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# define CALLER_ADDR5 0UL
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# define CALLER_ADDR6 0UL
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#endif
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#ifdef CONFIG_IRQSOFF_TRACER
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extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
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extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
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#else
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# define time_hardirqs_on(a0, a1) do { } while (0)
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# define time_hardirqs_off(a0, a1) do { } while (0)
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#endif
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#ifdef CONFIG_PREEMPT_TRACER
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extern void trace_preempt_on(unsigned long a0, unsigned long a1);
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extern void trace_preempt_off(unsigned long a0, unsigned long a1);
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#else
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# define trace_preempt_on(a0, a1) do { } while (0)
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# define trace_preempt_off(a0, a1) do { } while (0)
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#endif
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#ifdef CONFIG_CONTEXT_SWITCH_TRACER
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extern void
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ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
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#else
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static inline void
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ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
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#endif
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#endif /* _LINUX_FTRACE_H */
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